DE69028715T2 - CONVEYOR SYSTEM FOR CONVEYING OBJECTS IN SPACE - Google Patents

Abstract

A transport means for transporting pieces three-dimensionally, wherein the sections belonging to a section pair (1<1>, 1<2>; 4<1>, 4<2>) are box-like; a traction member (14<1>, 14<2>; 16<1>, 16<2>) has been disposed over its essential length inside the section (1<1>, 1<2>; 4<1>, 4<2>) and secured to the carriage with a tension means (31); and the transport means comprises return sheaves (15; 17), which have been placed in pairs, spaced at the distance of the section, with the carriage (2<1>, 2<2>; 5<1>, 5<2>) between the return sheaves; and the traction member has been disposed to run from the carriage over the return sheaves back to the respective carriage for forming a closed loop of the traction member and the respective carriage; and a power means (3, 6) has been arranged to move the traction member and by its mediation, the respective carriage.

Description

The present invention relates to a means of transport as defined in the preamble to claim 1.

Automation in industrial manufacturing and warehouses requires a variety of transport means capable of meeting different and constantly changing piece/part handling requirements. The variable quantities that require flexibility in parts handling systems include variable batch sizes, variable quantities to be moved/transported and variation in the sizes of parts. In addition, a relatively high level of transport and positioning accuracy is required from the parts handling systems. Transport and positioning accuracy refers to the transport means that transport each part in exact accordance with the paths intended for it and that are themselves positioned so that the true position of the transport means corresponds exactly to the position intended for it.

For use in such applications, a means of transport for transporting objects is known, comprising

a pair of side-by-side parallel and horizontal bridge sections, said bridge sections having a box-like configuration;

a pair of bridge carriages comprising propulsion means mounted thereon, the bridge carriages being supported by and movable on the bridge sections;

a pair of side-by-side parallel and horizontal transport sections located substantially at right angles to the pair of bridge sections, the transport sections being carried by the pair of bridge carriages and having a box-shaped configuration;

a pair of transport carriages with drive means, the transport carriages being mounted on the pair of transport sections and movable thereon;

a lifting frame carried by the transport trolleys;

a lifting means for lifting objects comprising drive means, wherein the lifting means is arranged on the lifting frame for vertically moving objects;

an elongate traction member on each of the bridge carriages for moving the transport sections and an elongate traction member on each of the transport sections for moving each transport carriage, the elongate traction members being arranged along and within a substantial part of the length of the sections;

Deflection pulleys arranged in pairs on the bridge sections and transport sections at a fixed distance between the deflection pulleys, a tension member of each pair of deflection pulleys extending from one end of each of the bridge and transport carriages over the deflection pulleys and back to said bridge and transport carriage at the other end thereof, so as to form a separate guide or loop for each tension member and each carriage;

Drive means associated with each pair of pulleys for moving the traction member and, in response, the corresponding bridge and transport carriages.

In a transport means of this type, which is known in the prior art, the arrangement known from document EP 0 200 694 can be used, in which the tension member is arranged so that it runs from the carriage and over the deflection pulleys back to the respective carriage in order to create a closed loop of the tension member and the respective carriage. Since it is important to maintain the accuracy of the transport and positioning in the transport means, the tension member must be pulled tight from time to time. In the transport means of document EP 0 200 694, this tensioning of the tension member has been solved by a construction in which one of the deflection pulleys is arranged adjustable with regard to its position in the longitudinal direction of the section, so that the distance between the deflection pulleys is adjustable.

The main problem inherent in such an arrangement for tensioning the tension member, as known from the prior art based on the document EP 0 200 694, is that only relatively short transport movements are possible in this application. This is due to the fact that the tensioning length that the tensioning means must provide increases with increasing length of the transport movement and with increasing length of the tension member. With the prior art arrangement, a transport movement length is achieved that is only in the order of 15 m. This maximum transport length means that the prior art tensioning means displaces the deflection pulley by approximately 0.8 to 1 m, which also depends on the extensibility of the tension member. In practice, it is extremely difficult to provide this and an adjustment tolerance that is larger than this. Therefore, the prior art tensioning means is too a size which limits the length of the transport movement. Furthermore, an adjustment size or tolerance provided at one end of the section takes up a considerable amount of space, with the result that the effective range in which the load can be transported becomes rather small in the case of the prior art clamping device arrangement.

Another problem inherent in the prior art arrangement is that the tensioning arrangement is complicated in terms of its construction. Moreover, the operation of tensioning the tension member can be excessively inconvenient because the tensioning must be carried out by tying it to a single point, and only by adjusting the pulley at one end of the section.

In one embodiment of the transport means, the tension member is a toothed belt. The tension member can of course equally be any other type of elongated tension member known in the art, for example a chain, a rope or the like. However, the use of a toothed belt is advantageous in this context because in this case no slippage of any kind can occur between the reversing discs and the toothed belt, and thus a precise transport movement is achieved. In addition, a toothed belt drive is noiseless and requires only little maintenance.

In one embodiment of the transport means, the bridge support comprises a roller unit arranged to run within the bridge section, and the bridge carriage is suspendedly mounted and supported by the roller unit.

In one embodiment of the transport means, the transport carriage comprises a roller unit arranged within of the transport section, and the transport carriage is suspended and supported by the roller unit.

When the roller unit runs within the section, a secure means of transport is achieved, the components of which cannot, under any circumstances, be separated from one another.

In one embodiment of the transport means, the drive means is connected to a reversing disk.

In one embodiment of the transport means, the transport means comprises a first sensor or scanner for determining the position of the bridge carriages, a second sensor or scanner for determining the position of the transport carriages, a third sensor or scanner for determining the position of the lifting means and control means for processing the signals from the sensors and for controlling the movements of the transport means.

In one embodiment of the transport means, the first, second and third sensors or scanners are angle sensors, preferably optical increment sensors, which can transmit signals to the control means. With the help of the sensors, the control means is enabled to precisely control the movement of the transport means. With the help of the sensor, the control means identifies the three-dimensional position of the transport means at any time and is thus enabled to control the movements in a previously programmed manner.

In one embodiment of the transport means, the lifting means comprises an upright beam or carrier provided with parallel guide rails attached on opposite sides; the lifting frame comprises guide roller units, and the guide rails and guide roller units are such arranged so that they interact to guide the vertical movement of the upright support.

In one embodiment of the transport means, the guide roller unit comprises two side wheels which come into contact with the guide rail on each side; the rotation axes of the side wheels are eccentric with respect to their bearing or fastening axes and the rotation of the fastening axes enables adjustment of the play between the guide rail and the side wheels. This allows the play between the guide rails of the upright beam and the side wheels to be set to a minimum, thereby minimizing undesirable lateral movements of the upright beam relative to the lifting frame.

In one embodiment of the transport means, the lifting means comprises a chain or equivalent connected to and parallel to the upright support; a drive wheel connected to the chain by means of a transmission gear; and a drive means arranged to set the drive wheel in rotation.

In one embodiment of the transport means, the drive wheel is arranged at a distance from the upright beam and the lifting means comprises deflection pulleys arranged to deflect the chain towards the drive wheel for travel. Such an arrangement includes the possibility that the drive wheel need not be arranged close to the upright beam, whereby space considerations do not cause problems when choosing the drive means and the transmission ratios.

In one embodiment of the transport means, the drive means is a squirrel-cage motor.

In one embodiment of the transport means, the drive means are squirrel-cage motors controlled by means of frequency converters in order to adjust the speeds. In the case of transport, it is advantageous to slow down the speeds of the various movements of the transport means just before stopping, so that stopping can take place at the right place with maximum accuracy.

In one embodiment of the transport means, the interior of the upright beam and the lifting frame forms a vacuum vessel for securing the vacuum for the vacuum-operated actuating means. The actuating means may, for example, be a vacuum-operated clamp which, for security, for example in the event of a power failure, requires a vacuum tank to ensure that the clamp does not release the load unexpectedly and at the wrong moment. The use of the interior of the upright beam or the lifting frame for the vacuum vessel is advantageous in view of achieving a compact arrangement in which no special, separate vacuum vessel is required which would only add to the weight of the structure and complicate it. The actuating means associated with the transport means may, of course, be any type of actuating means suitable for the particular application.

The invention is based on the important observation that with a combination of standard crane components it is possible to create a means of transport for the three-dimensional transport of parts, by means of which sufficient transport and positioning accuracy can be achieved at the same time. At the same time, the construction costs are a fraction of the initial costs of an equivalent state-of-the-art parts handling robot.

The advantage provided by the invention is that a means enabling automatically generated lifting and transport functions for relatively large masses can be produced at advantageous costs.

A further advantage of the invention is that the transport and positioning accuracy that can be achieved is high.

Furthermore, the invention provides a means of transport with a simple structure that is more or less maintenance-free.

In the following, the invention is described in detail with reference to the accompanying drawing, in which

Fig. 1 shows a means of transport according to an embodiment of the invention, viewed obliquely from above,

Fig. 2 shows a transport means according to an embodiment of the invention in side view,

Fig. 3 shows the means of transport of Fig. 2 when viewed from above,

Fig. 4 shows the guide roller arrangement of the lifting means of a transport means according to a third embodiment of the invention in section and in a view from above and

Fig. 5 shows the section V-V of Fig. 4.

In Fig. 1 a transport device for three-dimensional transport of parts is shown. The transport device comprises two side by side, parallel and horizontally arranged Bridge sections 1¹, 1², two bridge carriages 2¹, 2² provided with a drive means 3 and arranged to be movable on the bridge sections 1¹, 1² and in their direction; two transport sections 4¹, 4² lying next to each other, parallel to each other and horizontally, substantially at right angles to the bridge sections 1¹, 1² and arranged to be carried on the bridge carriages 2¹, 2²; two transport carriages 5¹, 5² provided with a drive means 6 and arranged to be mounted on the transport sections 4¹, 4² so as to be movable in their direction; a lifting frame 7 arranged to be carried by the transport carriages 5¹, 5²; a lifting means 8, which is provided with a drive means 9 and is mounted on the lifting frame so as to be movable in the vertical direction; a first sensor 10 for determining the position of the bridge carriages 2¹, 2²; a second sensor 11 for determining the position of the transport carriages 5¹, 5²; a third sensor for determining the position of the lifting means 8; and a control means 13 for processing the signals from the sensors 10, 11 and 12 and for controlling the movements of the transport means.

In the embodiment of Fig. 2, which is shown in elevation, one can see the elongated tension member 14¹, 14² associated with the bridge carriage 2,¹ 2². The transport means further comprises two reversing or deflecting pulleys 15 spaced apart by the distance of the bridge section 1¹, 1² with the bridge beam 21, 22 located between the deflecting pulleys 15. It also comprises a drive means 3 for moving the tension member 14¹, 14². The tension member is arranged in such a way that it runs from the bridge carriage over the reversing pulleys and back to the bridge carriage. The tension member 14¹ can be seen as shown in dashed line.

In the end view of Fig. 3, the elongated tension member 16¹, 16² can be seen, which belongs to the transport carriage 5¹, 5². The transport means further comprises two deflection or reversing disks 17 which are spaced apart at the distance of the transport section 4¹, 4², with the transport carriage 5¹, 5² being arranged between the deflection disks. It also comprises a drive means 6 for moving the tension member. The tension member runs from the transport carriage over the reversing disks and back to the transport carriage. The tension member 16¹ is shown in the figure with a dot-dash line.

The tension members 14¹, 14², 16¹ and 16² are toothed belts which are attached to the bridge and transport carriages 2¹, 2², 5¹, 5² by means of tensioning devices 31.

The reversing/deflection pulleys 15, 17 are arranged at the ends of the bridge sections 1¹, 1² and the transport sections 4¹, 4². The tension members 14¹, 14², 16¹, 16² are arranged so that they run within the sections. The drive means 3 is connected to the deflection pulleys at one end of the bridge sections, which are connected to one another by a transmission shaft. The drive means 6 is likewise connected to the deflection pulley at one end of the transport section. Separate drive means can of course be provided for each deflection pulley at one end of the section.

The drive means 3 and 6 can, for example, be squirrel-cage motors controlled by means of frequency converters, in which case the rotational speed of the motors and thus the speed of the movements of the transport means can be controlled as desired; for example, the speed is reduced slightly to a very low value before positioning, thereby achieving a high level of accuracy in stopping at a predetermined location.

The bridge carriages 2¹, 2² and the transport carriages 5¹, 5² comprise roller units 18 which are arranged to run within the bridge sections 1¹, 1² and the transport sections 4¹, 4².

The lifting means 8 comprises an upright beam or support 19 provided with parallel guide rails 20 fixed on opposite sides, in this case two such rails being provided. The lifting frame 7 comprises guide roller units 21, which in the present case are four in number. The guide rails 20 and the guide roller units 21 are arranged so that they cooperate to guide the vertical movement of the upright beam 19.

The lifting means 8 comprises a chain 25 or equivalent means connected to the upright beam 25 and parallel thereto. The drive wheel 26 belonging to the lifting means is connected to the chain via a drive transmission. The drive means 9 is arranged to drive the drive wheel. The drive means is preferably a squirrel-cage motor.

The drive wheel 26 is arranged at a distance from the upright beam 19, and the lifting means comprises traverse wheels 27 and 28 arranged to deflect the chain 25 towards the drive wheel.

The interiors of the upright beam 19 and the lifting frame 7 form a vacuum container to ensure the vacuum of the vacuum-operated actuating means 30.

The first 10, second 11 and third sensors 12 are pulse transformers, preferably optical increment transformers, which are arranged so that they can transmit signals to the control means 13.

The guide roller unit 21, shown in Fig. 4 and 5, comprises two side wheels 22 resting on each of their sides on the guide rail 20. The rotation axes 23 of the side wheels are offset eccentrically in relation to their bearing axes 24. By rotating the bearing axes 24, the play between the guide rail 20 and the side wheels 22 can be adjusted.

The invention is not limited to only the embodiments described in the foregoing numerous embodiments; rather, numerous modifications thereof can be made without departing from the scope of the inventive concept as defined by the claims.

Claims (14)

1. A means of transport for transporting objects, comprising a pair of parallel and horizontal bridge sections (11, 12) arranged side by side, said bridge sections having a box-like configuration; a pair of bridge carriages (2¹, 2²) comprising drive means (3) mounted thereon, the bridge carriages being supported by and movable on the bridge sections (1¹, 1²); a pair of parallel and horizontal transport sections (4¹, 4²) arranged side by side, which are located substantially at right angles to the pair of bridge sections (1¹, 1²), the transport sections being carried by the pair of bridge carriages (2¹, 2²) and having a box-shaped configuration; a pair of transport carriages (5¹, 5²) with drive means (6), the transport carriages being mounted on the pair of transport sections (4¹, 4²) and being movable thereon ; a lifting frame (7) carried by the transport carriages (5¹, 5²); a lifting means (8) for lifting objects comprising drive means (9), wherein the lifting means is arranged on the lifting frame (7) for vertically moving objects; an elongate traction member (14¹, 14²) on each of the bridge carriages (2¹, 2²) for moving the transport sections (4¹, 4²) and an elongate traction member (16¹, 16²) on each of the transport sections (4¹, 4²) for moving each transport carriage (5¹, 5²), the elongate traction members being arranged along and within a substantial part of the length of the sections; Deflection pulleys (15, 17) arranged in pairs on the bridge sections (1¹, 1²) and transport sections (4¹, 4²) at a fixed distance between the deflection pulleys, a tension member of each deflection pulley pair running from one end of each of the bridge and transport carriages over the deflection pulleys and back to said bridge and transport carriage at the other end thereof, so as to form a separate guide or loop for each tension member and each carriage; Drive means (3, 6) associated with each pair of pulleys (15, 17) for moving the tension member (14¹, 14², 16¹, 16²) and, in response thereto, the corresponding bridge and transport carriages (2¹, 2², 5¹, 5²), characterized in that tension adjusting means (31) are arranged on the bridge and transport carriages (2¹, 2², 5¹, 5²) between the pulleys (15, 17) for adjusting the tension of the elongated tension member (14¹, 14², 16¹, 16²) without adjusting the distance between the pulleys. 2. A transport means according to claim 1, wherein the lifting means comprises an upright beam provided with a pair of parallel guide rails for guiding the vertical movement of the carrier when an object is raised or lowered. 3. Transport means according to claim 1 or 2, characterized in that the tension member (14¹, 14², 16¹, 16²) is a toothed belt. 4. Transport means according to claim 1, 2 or 3, characterized in that the bridge support (2¹, 2²) comprises a roller unit (18) arranged to run within the bridge section (1¹, 1²), and that the bridge carriage is suspended and supported by the roller unit. 5. Transport means according to one of claims 1 to 4, characterized in that the transport carriage is arranged to run within the transport section (4¹, 4²) and that the transport carriage is suspended and supported by the roller unit. 6. Transport means according to one of claims 1 to 5, characterized in that the transport means comprises a first sensor or scanner (10) for determining the position of the bridge carriages (2¹, 2²), a second sensor or scanner (11) for determining the position of the transport carriages (5¹, 5²), a third sensor or scanner (12) for determining the position of the lifting means and control means (13) for processing the signals from the sensors and for controlling the movements of the transport means. 7. Transport means according to claim 6, characterized in that the first (10), second (11) and third (12) sensors are pulse transmitters, preferably optical increment transmitters, which are used for Transmitting signals to the control means (13). 8. Transport means according to one of claims 1 to 7, characterized in that the lifting means (8) comprises an upright beam or support (19), provided with parallel guide rails (20) fastened on opposite sides, that the lifting frame (7) comprises guide roller units (21) and that the guide rails and guide roller units are arranged in such a way that they cooperate to guide the vertical movement of the upright support. 9. Transport means according to claim 8, characterized in that the guide roller unit (21) comprises two side wheels (22) which come to rest on each side against the guide rail (20), that the rotation axes (23) of the side wheels are eccentric with respect to their fastening axes (24) and that the play between the guide rail and the side wheels can be adjusted by rotating the fastening axes. 10. Transport means according to claim 8 or 9, characterized in that the lifting means (8) comprises a chain (25) or an equivalent connected to the upright support (19) and parallel thereto; a drive wheel (26) connected to the chain by means of a transmission gear; and a drive means (9) arranged to set the drive wheel in rotation. 11. Transport means according to claim 10, characterized in that the drive wheel (26) is arranged at a distance from the upright support and the lifting means comprises lateral wheels (27 and 28) which are arranged to deflect the chain (25) to the drive wheel. 12. Transport means according to one of claims 1 to 11, characterized in that the drive means (3, 6, 9) is a squirrel-cage motor. 13. Means of transport according to one of claims 1 to 12, characterized in that the drive means (3 and 6) are short-circuit motors which are controlled with the aid of frequency converters for controlling the speeds. 14. Transport means according to one of claims 1 to 13, characterized in that the interior of the upright support (19) and/or the lifting frame (7) form a vacuum container for securing the vacuum for the vacuum-operated actuating means (30).